/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2008, by Object Refinery Limited and Contributors.
 *
 * Project Info:  http://www.jfree.org/jfreechart/index.html
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
 * in the United States and other countries.]
 *
 * ---------------------------
 * CategoryCrosshairState.java
 * ---------------------------
 * (C) Copyright 2008, by Object Refinery Limited and Contributors.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * Changes
 * -------
 * 26-Jun-2008 : Version 1 (DG);
 *
 */

package net.droidsolutions.droidcharts.core.plot;

import net.droidsolutions.droidcharts.awt.Point2D;
import net.droidsolutions.droidcharts.core.renderer.CategoryItemRenderer;

/**
 * Represents state information for the crosshairs in a {@link CategoryPlot}. An
 * instance of this class is created at the start of the rendering process, and
 * updated as each data item is rendered. At the end of the rendering process,
 * this class holds the row key, column key and value for the crosshair
 * location.
 * 
 * @since 1.0.11
 */
public class CategoryCrosshairState extends CrosshairState {

	/**
	 * The row key for the crosshair point.
	 */
	private Comparable rowKey;

	/**
	 * The column key for the crosshair point.
	 */
	private Comparable columnKey;

	/**
	 * Creates a new instance.
	 */
	public CategoryCrosshairState() {
		this.rowKey = null;
		this.columnKey = null;
	}

	/**
	 * Returns the row key.
	 * 
	 * @return The row key.
	 */
	public Comparable getRowKey() {
		return this.rowKey;
	}

	/**
	 * Sets the row key.
	 * 
	 * @param key
	 *            the row key.
	 */
	public void setRowKey(Comparable key) {
		this.rowKey = key;
	}

	/**
	 * Returns the column key.
	 * 
	 * @return The column key.
	 */
	public Comparable getColumnKey() {
		return this.columnKey;
	}

	/**
	 * Sets the column key.
	 * 
	 * @param key
	 *            the key.
	 */
	public void setColumnKey(Comparable key) {
		this.columnKey = key;
	}

	/**
	 * Evaluates a data point from a {@link CategoryItemRenderer} and if it is
	 * the closest to the anchor point it becomes the new crosshair point.
	 * 
	 * @param rowKey
	 *            the row key.
	 * @param columnKey
	 *            the column key.
	 * @param value
	 *            y coordinate (measured against the range axis).
	 * @param datasetIndex
	 *            the dataset index for this point.
	 * @param transX
	 *            x translated into Java2D space.
	 * @param transY
	 *            y translated into Java2D space.
	 * @param orientation
	 *            the plot orientation.
	 */
	public void updateCrosshairPoint(Comparable rowKey, Comparable columnKey,
			double value, int datasetIndex, double transX, double transY,
			PlotOrientation orientation) {

		Point2D anchor = getAnchor();
		if (anchor != null) {
			double xx = anchor.getX();
			double yy = anchor.getY();
			if (orientation == PlotOrientation.HORIZONTAL) {
				double temp = yy;
				yy = xx;
				xx = temp;
			}
			double d = (transX - xx) * (transX - xx) + (transY - yy)
					* (transY - yy);

			if (d < getCrosshairDistance()) {
				this.rowKey = rowKey;
				this.columnKey = columnKey;
				setCrosshairY(value);
				setDatasetIndex(datasetIndex);
				setCrosshairDistance(d);
			}
		}

	}

	/**
	 * Updates only the crosshair row and column keys (this is for the case
	 * where the range crosshair does NOT lock onto the nearest data value).
	 * 
	 * @param rowKey
	 *            the row key.
	 * @param columnKey
	 *            the column key.
	 * @param datasetIndex
	 *            the dataset axis index.
	 * @param transX
	 *            the translated x-value.
	 * @param orientation
	 *            the plot orientation.
	 */
	public void updateCrosshairX(Comparable rowKey, Comparable columnKey,
			int datasetIndex, double transX, PlotOrientation orientation) {

		Point2D anchor = getAnchor();
		if (anchor != null) {
			double anchorX = anchor.getX();
			if (orientation == PlotOrientation.HORIZONTAL) {
				anchorX = anchor.getY();
			}
			double d = Math.abs(transX - anchorX);
			if (d < getCrosshairDistance()) {
				this.rowKey = rowKey;
				this.columnKey = columnKey;
				setDatasetIndex(datasetIndex);
				setCrosshairDistance(d);
			}
		}

	}

}
